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One motor idles slower?

Discussion in 'Phantom 2 Discussion' started by tferrari, Aug 12, 2014.

  1. tferrari

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    Just took my new P2 out of the box, upgraded to 3.06, did advanced calibration and controller calibration in the P2 assistant software. Did field compass calibration and flew the P2 a little in Phantom mode.

    It seems to fly well in GPS mode but one motor is noticeably stiffer when the rotor is spun by hand and visually slower when the P2 is just idling. That slow motor pulses every couple of seconds at idle very consistently too.

    Is this an issue?

    Lastly, when the P2 is turned on, the startup sounds are delayed between the two speakers that output them. My last P2 didnt have either of these issues.

    Thoughts?
     
  2. UrAwFuL

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    I'm pretty sure theres an issue if there are any delays than usual.

    Fun fact: Startup sounds comes from the motors itself. :lol:
     
  3. tferrari

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    The dealer is overnighting me a new motor and assures me that he'll resolve the issue.

    Cool fact about those sounds by the way!
     
  4. UrAwFuL

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    Yep. Apparently it makes the sounds via high frequency vibrations.. it's fairly evident if you touch the motors while it starts up.

    At least that's what I've been reading how it happens, but I do feel the vibrations on startup.. :lol:
     
  5. tferrari

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    I agree that the speed controller is somehow creating those sounds.

    I installed a new motor and the issue is mostly corrected at idle but I can still see the slightly lower speed. I really do think it's the motor speed controller, but I'm not about to start changing things in the Phantom considering the unit flies perfectly without any symptoms. It no longer makes that 'pulsing' RPM increase sound, which was very unnerving.

    Thanks.
     
  6. bas4241

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    Sounds like an ESC problem to me....better to replace it (they are cheap) than to have it quit or go crazy at 300 feet! :shock:
     
  7. tferrari

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    They are pretty cheap.. I'll replace it. You're probably right man...
     
  8. ianwood

    ianwood Taco Wrangler
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    If it is a physical resistance issue with the motor itself, you should be able to tell by comparing it's temperature with the other motors. In fact, it's good practice in general to "cop a feel" of each of your motors after you land to look for early signs of bearing failure or other mechanical issues that can ruin your next flight.
     
  9. tferrari

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    When turning that motor, it feels like it has greater resistance to turning (maybe 20% greater?) but it felt like an issue with the magnets/magnetic field to me, but that could simply be confirmation bias; it may in fact have something to do with the bearings. I'm not sure as I haven't opened up one of these motors to see its design.

    I replaced the motor with a 'normal-functioning' extra motor I had from a spare parts phantom and the issue got a little bit better but it still persists. I have a feeling that it's an ESC.

    Thanks for the reply Ian.
     
  10. Xrover

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    I just purchased a new P2 W/ZH3-3D.
    I noticed that when Stopping the motors, the front right will spin down much slower then the others. The others stop spinning pretty quickly but the front right seems to freewheel about 2 seconds longer. If I hand rotate all the motors, the front right is much easier to spin. If i pull the battery, wait a couple seconds, that motor hand rotates just like the others. No difference in feel at that point.

    Flight sounds seem the same.

    I don't recall seeing this on my previous P2.
     
  11. UrAwFuL

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    Actually, sometimes my back left motor starts late and I noticed the spin looks different than the others (looks slower) after putting everything back together after reorganizing my wires. I did a manual turn and I feel a bit of resistance more than the other three.
     
  12. Aquaneo

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    That's funny, my front right seems slower on my video feed as well. But the P2 flies just fine.
     
  13. Geo74

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    Well I had the same problem as you when I bought my new Phantom 2 .
    I thought about the motor. Replcaced it and the situation got better but still the motor idled at slower rpm. More specific the 3 motors idle at arounnd 1500 rpms and the other one at 1200 -1300
    Maybe is an ESC issue maybe not.
    However I have until now over 40 hours of flight without any issues .
    Flies perfect!
     
  14. tom3holer

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    There is a known issue with the QC of the phantom motors.
    When spinning the motors by hand usually one or more will seem tighter to some extent than the others. This is due to the lack of QC on these motors and it can be corrected.
    There is a brass spacer on each motor that can carefully be sanded down after removing the c-clip in the bottom.

    Tom
     
  15. Geo74

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    PS I fotgot! I replaced 2 motors ( at the same position), because of mulfunction due to debris insertion, with the same rpm results so I am convinced that the specific ESC turns the motor at lower idle speed, but as I said it flies perfect
     
  16. UrAwFuL

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    I used my camera to record the my motor start at 400 fps just now. Maybe someone could check it out if my motors are really acting weird. :lol:

    This is literally 5 seconds expanded into a minute.

    Note that my problematic motor is the back left (or the motor on the far right on the video) because I noticed the propeller spins look different than the rest.

    Also noticed the derp on my front right motor (or far left on video) which is normal, right? :?

    What you guys think?

    [youtube]https://www.youtube.com/watch?v=m5GHCAfmqLg[/youtube]
     
  17. tferrari

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    I have a slower motor as well, but it only appears at idle. I've changed a motor myself with little resolution.

    There are no symptoms during flight.

    I believe it's an ESC issue and I'll report back once I change the speed controller (give me a week).